Question to the HM Treasury:

To ask the Chancellor of the Exchequer, what proportion of unpaid tax liabilities is written off each year; and according to what criteria HMRC determines when a tax debt will no longer be pursued.

HMRC is committed to closing the tax gap further and tackling non-compliant behaviours such as tax evasion, tax avoidance, criminal attacks, error, failure to take reasonable care, hidden economy activity, legal interpretation issues, and non-payment.

In 2024 to 2025, HMRC’s compliance work contributed to record tax revenues of £875.9 billion, collecting and protecting £48 billion of tax that would have gone unpaid if HMRC hadn’t stepped in – up from £41.8 billion the previous year.

At the Autumn Budget 2025, the government announced a package of measures that will raise a further £2.4 billion in additional tax revenues in 2029 to 2030. This builds on announcements at Autumn Budget 2024 (£6.5 billion), and Spring Statement 2025 (over £1 billion) and brings the total revenue from closing the tax gap announced this Parliament to £10 billion in 2029 to 2030.

HMRC pursues unpaid tax liabilities through a number of routes. Those who have not paid will be subject to initial telephone and letter campaigns to encourage swift payment. HMRC also uses private sector debt collection agencies to pursue outstanding amounts. Cases will move between these different stages of the debt collection process as part of being worked.

Where payments remain outstanding, HMRC has a range of enforcement powers to address the small minority of taxpayers who deliberately refuse to pay or engage, such as taking control of goods, recovering debt through county court proceedings, and applying to make a company or person insolvent.

HMRC also publishes its Annual Report and Accounts on GOV.UK, which reports on its annual tax losses and sets out the limited circumstances in which a debt may no longer be pursued.

HMRC records its debt cases by tax regime, rather than customer type, and does not organise cases by specifically which stage of the debt collection process it is at.